Multi-speed dual-clutch planetary transmission mechanisms having four gear sets and a stationary member

ABSTRACT

The family of transmissions has a plurality of members that can be utilized in powertrains to provide at least six forward speed ratios and one reverse speed ratio. The transmission family members include four planetary gear sets, two input clutches, eight or nine torque transmitting mechanisms, three fixed interconnections, and one grounded planetary gear member. The invention provides a low content multi-speed dual clutch transmission mechanism wherein the two input clutches alternately connect the engine to realize odd and even speed ratio changes. The torque transmitting mechanisms provide connections between various gear members, the fixed interconnections, the input clutches, the output shaft, and the transmission housing, and are operated in combinations of three to establish at least five forward speed ratios and at least one reverse speed ratio.

TECHNICAL FIELD

[0001] The present invention relates to a family of power transmissionshaving two input clutches which selectively connect an input shaft tofirst and second pairs of planetary gear sets to provide at least sixforward speed ratios and one reverse speed ratio.

BACKGROUND OF THE INVENTION

[0002] Passenger vehicles include a powertrain that is comprised of anengine, multi-speed transmission, and a differential or final drive. Themulti-speed transmission increases the overall operating range of thevehicle by permitting the engine to operate through its torque range anumber of times.

[0003] A primary focus of transmission and engine design work is in thearea of increasing vehicle fuel efficiency. Manual transmissionstypically provide improved vehicle fuel economy over automatictransmissions because automatic transmissions use a torque converter forvehicle launch and multiple plate hydraulically-applied clutches forgear engagement. Clutches of this type, left unengaged or idling, imposea parasitic drag torque on a drive line due to the viscous shearingaction which exists between the plates and discs rotating at differentspeeds relative to one another. This drag torque adversely affectsvehicle fuel economy for automatic transmissions. Also, the hydraulicpump that generates the pressure needed for operating theabove-described clutches further reduces fuel efficiency associated withautomatic transmissions. Manual transmissions eliminate these problems.

[0004] While manual transmissions are not subject to the above describedfuel efficiency related problems, manual transmissions typically providepoor shift quality because a significant torque interruption is requiredduring each gear shift as the engine is disengaged from the transmissionby the clutch to allow shafts rotating at different speeds to besynchronized.

[0005] So called “automated manual” transmissions provide electronicshifting in a manual transmission configuration which, in certaincircumstances, improves fuel efficiency by eliminating the parasiticlosses associated with the torque converter and hydraulic pump neededfor clutching. Like manual transmissions, a drawback of automated manualtransmissions is that the shift quality is not as high as an automatictransmission because of the torque interruption during shifting.

[0006] So called “dual-clutch automatic” transmissions also eliminatethe torque converter and replace hydraulic clutches with synchronizersbut they go further to provide gear shift quality which is superior tothe automated manual transmission and similar to the conventionalautomatic transmission, which makes them quite attractive. However, mostknown dual-clutch automatic transmissions include a lay shaft orcountershaft gear arrangement, and have not been widely applied invehicles because of their complexity, size and cost. For example, a dualclutch lay shaft transmission could require eight sets of gears, twoinput/shift clutches and seven synchronizers/dog clutches to provide sixforward speed ratios and a reverse speed ratio. An example of adual-clutch automatic transmission is described in U.S. Pat. No.5,385,064, which is hereby incorporated by reference.

SUMMARY OF THE INVENTION

[0007] The invention provides a low content multi-speed dual-clutchtransmission family utilizing planetary gear sets rather than lay shaftgear arrangements. In particular, the invention includes four planetarygear sets, two input/shift clutches, and nine selectable torquetransmitting mechanisms to provide at least six forward speed ratios anda reverse speed ratio.

[0008] According to one aspect of the invention, the family oftransmissions has four planetary gear sets, each of which includes afirst, second and third member, which members may comprise a sun gear,ring gear, or a planet carrier assembly member.

[0009] In referring to the first, second, third and fourth gear sets inthis description and in the claims, these sets may be counted “first” to“fourth” in any order in the drawings (i.e. left-to-right,right-to-left, etc.).

[0010] In another aspect of the present invention, each of the planetarygear sets may be of the single pinion type or of the double pinion type.

[0011] In yet another aspect of the present invention, the first memberof the first planetary gear set is continuously connected with the firstmember of the second planetary gear set through a first interconnectingmember.

[0012] In yet another aspect of the present invention, the second memberof the first planetary gear set is continuously connected with thesecond member of the second planetary gear set through a secondinterconnecting member.

[0013] In yet another aspect of the present invention, a member of thefirst or second planetary gear set is continuously connected with thefirst member of the third planetary gear set and the output shaftthrough a third interconnecting member.

[0014] In yet another aspect of the present invention, the first memberof the fourth planetary gear set is continuously connected with astationary member (transmission housing).

[0015] In accordance with a further aspect of the invention, a firstinput clutch selectively connects the input shaft with a members of thefirst or second planetary gear set through other torque-transmittingmechanisms, such as synchronizers.

[0016] In accordance with another aspect of the present invention, asecond input clutch selectively connects the input shaft with the secondmember of the third planetary gear set.

[0017] In another aspect of the invention, first and second torquetransmitting mechanisms, such as rotating synchronizers, selectivelyconnect members of the first and second planetary gear sets with thefirst input clutch.

[0018] In still a further aspect of the invention, third, fourth, fifth,and sixth torque transmitting mechanisms, such as rotatingsynchronizers, selectively connect members of the third planetary gearset with members of the fourth planetary gear set.

[0019] In still another aspect of the invention, seventh and eighthtorque transmitting mechanisms, such as braking synchronizers,selectively connect members of the first or second planetary gear setwith the stationary member.

[0020] In a further aspect of the invention, a ninth torque transmittingmechanism, such as a rotating synchronizer, selectively connects amember of the first or second planetary gear set with the first inputclutch. Alternatively, the ninth torque transmitting mechanism, such asa braking synchronizer, selectively connects a member of the first orsecond planetary gear set to the stationary member.

[0021] In accordance with a further aspect of the invention, the inputclutches and torque transmitting mechanisms are selectively engaged incombinations of at least three to provide at least six forward speedratios and a reverse speed ratio.

[0022] In accordance with a further aspect of the invention, the firstinput clutch is applied for odd number speed ranges, and the secondinput clutch is applied for even number speed ranges, or vice versa.

[0023] In another aspect of the invention, the first input clutch andthe second input clutch are interchanged (i.e. alternately engaged) toshift from odd number speed range to even number speed range, or viceversa.

[0024] In accordance with a further aspect of the invention, eachselected torque transmitting mechanism for a new speed ratio is engagedprior to shifting of the input clutches to achieve shifts without torqueinterruptions.

[0025] In accordance with a further aspect of the invention, at leastone pair of synchronizers is executed as a double synchronizer to reducecost and package size.

[0026] In accordance with a further aspect of the invention, the firstinput clutch can be eliminated and the first and second torquetransmitting mechanism can be used as input clutches to further reducecontent.

[0027] In accordance with a further aspect of the invention, at leastone of the torque transmitting mechanisms can be eliminated to realizefive forward speed ratios and a reverse speed ratio.

[0028] The above objects, features, advantages, and other objects,features, and advantages of the present invention are readily apparentfrom the following detailed description of the best modes for carryingout the invention when taken in connection with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029]FIG. 1a is a schematic representation of a powertrain including aplanetary transmission incorporating a family member of the presentinvention;

[0030]FIG. 1b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 1a;

[0031]FIG. 2a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0032]FIG. 2b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 2a;

[0033]FIG. 3a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0034]FIG. 3b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 3a;

[0035]FIG. 4a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0036]FIG. 4b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 4a;

[0037]FIG. 5a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0038]FIG. 5b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 5a;

[0039]FIG. 6a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0040]FIG. 6b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 6a;

[0041]FIG. 7a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0042]FIG. 7b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 7a;

[0043]FIG. 8a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0044]FIG. 8b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 8a;

[0045]FIG. 9a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0046]FIG. 9b is a truth table and chart depicting some of the operatingcharacteristics of the powertrain shown in FIG. 9a;

[0047]FIG. 10a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention;

[0048]FIG. 10b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 10a;

[0049]FIG. 11a is a schematic representation of a powertrain having aplanetary transmission incorporating another family member of thepresent invention; and

[0050]FIG. 11b is a truth table and chart depicting some of theoperating characteristics of the powertrain shown in FIG. 11a.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0051] Referring to the drawings, wherein like characters represent thesame or corresponding parts throughout the several views, there is shownin FIG. 1a a powertrain 10 having a conventional engine 12, a planetarytransmission 14, and a conventional final drive mechanism 16.

[0052] The planetary transmission 14 includes an input shaft 17continuously connected with the engine 12, a planetary gear arrangement18, and an output shaft 19 continuously connected with the final drivemechanism 16. The planetary gear arrangement 18 includes four planetarygear sets 20, 30, 40 and 50.

[0053] The planetary gear set 20 includes a sun gear member 22, a ringgear member 24, and a planet carrier assembly member 26. The planetcarrier assembly member 26 includes a plurality of pinion gears 27rotatably mounted on a carrier member 29 and disposed in meshingrelationship with both the sun gear member 22 and the ring gear member24.

[0054] The planetary gear set 30 includes a sun gear member 32, a ringgear member 34, and a planet carrier assembly member 36. The planetcarrier assembly member 36 includes a plurality of pinion gears 37rotatably mounted on a carrier member 39 and disposed in meshingrelationship with both the sun gear member 32 and the ring gear member34.

[0055] The planetary gear set 40 includes a sun gear member 42, a ringgear member 44, and a planet carrier assembly member 46. The planetcarrier assembly member 46 includes a plurality of intermeshing piniongears 47, 48 rotatably mounted on a carrier member 49 and disposed inmeshing relationship with the ring gear member 44 and the sun gearmember 42, respectively.

[0056] The planetary gear set 50 includes a sun gear member 52, a ringgear member 54, and a planet carrier assembly member 56. The planetcarrier assembly member 56 includes a plurality of pinion gears 57rotatably mounted on a carrier member 59 and disposed in meshingrelationship with both the sun gear member 52 and the ring gear member54.

[0057] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 20, 30, 40 and 50 are divided into first andsecond transmission subsets 60, 61 which are alternatively engaged toprovide odd number and even number speed ranges, respectively.Transmission subset 60 includes planetary gear sets 20 and 30, andtransmission subset 61 includes planetary gear sets 40 and 50. Theoutput shaft 19 is continuously connected with members of both subsets60 and 61.

[0058] As mentioned above, the first and second input clutches 62, 63are alternatively engaged for transmitting power from the input shaft 17to transmission subset 60 or transmission subset 61. The first andsecond input clutches 62, 63 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 60, 61 prior to engaging therespective input clutches 62, 63. The preselection is achieved by meansof electronically controlled synchronizers. As shown, the planetary geararrangement includes nine torque transmitting mechanisms 64, 65, 66, 67,68, 69, 70, 71 and 72. The torque transmitting mechanisms 64 and 65comprise braking synchronizers, and the torque transmitting mechanisms66, 67, 68, 69, 70, 71 and 72 comprise rotating synchronizers.

[0059] The braking synchronizers and rotating synchronizers arereferenced in the claims as follows: first and second torquetransmitting mechanisms 66, 67; third, fourth, fifth and sixth torquetransmitting mechanisms 69, 70, 71, 72; seventh and eighth torquetransmitting mechanisms 64, 65; and ninth torque transmitting mechanism68. Other family members are similarly referenced in the claims (i.e.two torque transmitting mechanisms from left transmission subset, fourtorque transmitting mechanisms from right transmission subset, twobrakes from left transmission subset, and then additional torquetransmitting mechanism (clutch or brake) from left transmission subset).

[0060] By way of example, synchronizers which may be implemented as therotating and/or braking synchronizers referenced herein are shown in thefollowing patents, each of which are incorporated by reference in theirentirety: U.S. Pat. Nos. 5,651,435; 5,975,263; 5,560,461; 5,641,045;5,497,867; 6,354,416.

[0061] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 60, 61 (i.e. through the clutch 62to the synchronizers 66, 67, 68 and through the clutch 63 to the ringgear member 44). The planet carrier assembly member 26 is continuouslyconnected with the ring gear member 34 through the interconnectingmember 74. The ring gear member 24 is continuously connected with thesun gear member 32 through the interconnecting member 76. The planetcarrier assembly member 36 is continuously connected with the planetcarrier assembly member 46 and the output shaft 19 through theinterconnecting member 78. The ring gear member 54 is continuouslyconnected with the transmission housing 80.

[0062] The sun gear member 22 is selectively connectable with thetransmission housing 80 through the braking synchronizer 64. The planetcarrier assembly member 26 is selectively connectable with thetransmission housing 80 through the braking synchronizer 65. The sungear member 22 is selectively connectable with the input shaft 17through the input clutch 62 and the rotating synchronizer 66. The sungear member 32 is selectively connectable with the input shaft 17through the input clutch 62 and the rotating synchronizer 67. The planetcarrier assembly member 26 is selectively connectable with the inputshaft 17 through the input clutch 62 and the rotating synchronizer 68.The planet carrier assembly member 46 is selectively connectable withthe planet carrier assembly member 56 through the rotating synchronizer69. The planet carrier assembly member 46 is selectively connectablewith the sun gear member 52 through the rotating synchronizer 70. Thesun gear member 42 is selectively connectable with the planet carrierassembly member 56 through the rotating synchronizer 71. The sun gearmember 42 is selectively connectable with the sun gear member 52 throughthe rotating synchronizer 72.

[0063] As shown in FIG. 1b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

[0064] The reverse speed ratio is established with the engagement of theinput clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 66. The input clutch 62 and the rotating synchronizer 66connect the sun gear member 22 to the input shaft 17. The brakingsynchronizer 65 connects the planet carrier assembly member 26 to thetransmission housing 80. The sun gear member 22 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 26 andthe ring gear member 34 do not rotate. The ring gear member 24 rotatesat the same speed as the sun gear member 32. The ring gear member 24rotates at a speed determined from the speed of the sun gear member 22and the ring gear/sun gear tooth ratio of the planetary gear set 20. Theplanet carrier assembly members 36, 46 rotate at the same speed as theoutput shaft 19. The planet carrier assembly member 36, and thereforethe output shaft 19, rotates at a speed determined from the speed of thesun gear member 32 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The numerical value of the reverse speed ratio isdetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30.

[0065] The first forward speed ratio is established with the engagementof the input clutch 62, the braking synchronizer 65 and the rotatingsynchronizer 67. The input clutch 62 and the rotating synchronizer 67connect the sun gear member 32 to the input shaft 17. The brakingsynchronizer 65 connects the planet carrier assembly member 26 to thetransmission housing 80. The ring gear member 24 and the sun gear member32 rotate at the same speed as the input shaft 17. The planet carrierassembly member 26 and the ring gear member 34 do not rotate. The planetcarrier assembly members 36, 46 rotate at the same speed as the outputshaft 19. The planet carrier assembly member 36, and therefore theoutput shaft 19, rotates at a speed determined from the speed of the sungear member 32 and the ring gear/sun gear tooth ratio of the planetarygear set 30. The numerical value of the first forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 30.

[0066] The second forward speed ratio is established with the engagementof the input clutch 63 and the rotating synchronizers 69, 72. The inputclutch 63 connects the ring gear member 44 to the input shaft 17. Therotating synchronizer 69 connects the planet carrier assembly member 36to the planet carrier assembly member 46. The rotating synchronizer 72connects the sun gear member 42 to the sun gear member 52. The ring gearmember 44 rotates at the same speed as the input shaft 17. The planetcarrier assembly members 46, 56 rotate at the same speed as the outputshaft 19. The sun gear member 42 rotates at the same speed as the sungear member 52. The planet carrier assembly member 46, and therefore theoutput shaft 19, rotates at a speed determined from the speed of thering gear member 44, the speed of the sun gear member 42 and the ringgear/sun gear tooth ratio of the planetary gear set 40. The ring gearmember 54 does not rotate. The planet carrier assembly member 56 rotatesat a speed determined from the speed of the sun gear member 52 and thering gear/sun gear tooth ratio of the planetary gear set 50. Thenumerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets40, 50.

[0067] The third forward speed ratio is established with the engagementof the input clutch 62, the braking synchronizer 64 and the rotatingsynchronizer 67. The input clutch 62 and the rotating synchronizer 67connect the sun gear member 32 to the input shaft 17. The brakingsynchronizer 64 connects the sun gear member 22 to the transmissionhousing 80. The sun gear member 22 does not rotate. The planet carrierassembly member 26 rotates at the same speed as the ring gear member 34.The ring gear member 24 and the sun gear member 32 rotate at the samespeed as the input shaft 17. The planet carrier assembly member 26rotates at a speed determined from the speed of the ring gear member 24and the ring gear/sun gear tooth ratio of the planetary gear set 20. Theplanet carrier assembly members 36, 46 rotate at the same speed as theoutput shaft 19. The planet carrier assembly member 36, and thereforethe output shaft 19, rotates at a speed determined from the speed of thering gear member 34, the speed of the sun gear member 32 and the ringgear/sun gear tooth ratio of the planetary gear set 30. The numericalvalue of the third forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 20, 30.

[0068] The fourth forward speed ratio is established with the engagementof the input clutch 63 and the rotating synchronizers 69, 71. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the fourth forward speed ratio is 1.

[0069] The fifth forward speed ratio is established with the engagementof the input clutch 62, the braking synchronizer 64 and the rotatingsynchronizer 68. The input clutch 62 and the rotating synchronizer 68connect the planet carrier assembly member 26 to the input shaft 17. Thebraking synchronizer 64 connects the sun gear member 22 to thetransmission housing 80. The sun gear member 22 does not rotate. Theplanet carrier assembly member 26 and the ring gear member 34 rotate atthe same speed as the input shaft 17. The ring gear member 24 rotates atthe same speed as the sun gear member 32. The ring gear member 24rotates at a speed determined from the speed of the planet carrierassembly member 26 and the ring gear/sun gear tooth ratio of theplanetary gear set 20. The planet carrier assembly members 36, 46 rotateat the same speed as the output shaft 19. The planet carrier assemblymember 36, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the ring gear member 34, the speed of thesun gear member 32 and the ring gear/sun gear tooth ratio of theplanetary gear set 30. The numerical value of the fifth forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 20, 30.

[0070] The sixth forward speed ratio is established with the engagementof the input clutch 63 and the rotating synchronizers 70, 71. The inputclutch 63 connects the ring gear member 44 to the input shaft 17. Therotating synchronizer 70 connects the planet carrier assembly member 46to the sun gear member 52. The rotating synchronizer 71 connects the sungear member 42 to the planet carrier assembly member 56. The sun gearmember 42 rotates at the same speed as the planet carrier assemblymember 56. The planet carrier assembly member 46 and the sun gear member52 rotate at the same speed as the output shaft 19. The ring gear member44 rotates at the same speed as the input shaft 17. The planet carrierassembly member 46, and therefore the output shaft 19, rotates at aspeed determined from the speed of the ring gear member 44, the speed ofthe sun gear member 42 and the ring gear/sun gear tooth ratio of theplanetary gear set 40. The ring gear member 54 does not rotate. Theplanet carrier assembly member 56 rotates at a speed determined from thespeed of the sun gear member 52 and the ring gear/sun gear tooth ratioof the planetary gear set 50. The numerical value of the sixth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratiosof the planetary gear sets 40, 50.

[0071] As set forth above, the engagement schedule for the torquetransmitting mechanisms is shown in the truth table of FIG. 1b. Thistruth table also provides an example of speed ratios that are availableutilizing the ring gear/sun gear tooth ratios given by way of example inFIG. 1b. The R1/S1 value is the tooth ratio of the planetary gear set20; the R2/S2 value is the tooth ratio of the planetary gear set 30; theR3/S3 value is the tooth ratio of the planetary gear set 40; and theR4/S4 value is the tooth ratio of the planetary gear set 50. Also, thechart of FIG. 1b describes the ratio steps that are attained utilizingthe sample of tooth ratios given. For example, the step ratio betweenfirst and second forward speed ratios is 1.49, while the step ratiobetween the reverse and first forward ratio is −1.52. Those skilled inthe art will recognize that since torque transmitting mechanisms 66, 68(67) are connected to a common member, input clutch 62, and they are notengaged at the same time for any of the speed ratios, the pair can beexecuted as a double (triple) synchronizer to reduce content and cost.Similarly, torque transmitting mechanisms pair 71, 72 can be implementedas a double synchronizer.

[0072]FIG. 2a shows a powertrain 110 having a conventional engine 12, aplanetary transmission 114, and a conventional final drive mechanism 16.The planetary transmission 114 includes an input shaft 17 connected withthe engine 12, a planetary gear arrangement 118, and an output shaft 19connected with the final drive mechanism 16. The planetary geararrangement 118 includes four planetary gear sets 120, 130, 140 and 150.

[0073] The planetary gear set 120 includes a sun gear member 122, a ringgear member 124, and a planet carrier assembly member 126. The planetcarrier assembly member 126 includes a plurality of intermeshing piniongears 127, 128 rotatably mounted on a carrier member 129 and disposed inmeshing relationship with the ring gear member 124 and the sun gearmember 122, respectively.

[0074] The planetary gear set 130 includes a sun gear member 132, a ringgear member 134, and a planet carrier assembly member 136. The planetcarrier assembly member 136 includes a plurality of pinion gears 137rotatably mounted on a carrier member 139 and disposed in meshingrelationship with both the sun gear member 132 and the ring gear member134.

[0075] The planetary gear set 140 includes a sun gear member 142, a ringgear member 144, and a planet carrier assembly member 146. The planetcarrier assembly member 146 includes a plurality of intermeshing piniongears 147, 148 rotatably mounted on a carrier member 149 and disposed inmeshing relationship with the ring gear member 144 and the sun gearmember 142, respectively.

[0076] The planetary gear set 150 includes a sun gear member 152, a ringgear member 154, and a planet carrier assembly member 156. The planetcarrier assembly member 156 includes a plurality of pinion gears 157rotatably mounted on a carrier member 159 and disposed in meshingrelationship with both the sun gear member 152 and the ring gear member154.

[0077] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 120, 130, 140 and 150 are divided into firstand second transmission subsets 160, 161 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 160 includes planetary gear sets 120 and 130, andtransmission subset 161 includes planetary gear sets 140 and 150. Theoutput shaft 19 is continuously connected with members of both subsets160 and 161.

[0078] As mentioned above, the first and second input clutches 162, 163are alternatively engaged for transmitting power from the input shaft 17to transmission subset 160 or transmission subset 161. The first andsecond input clutches 162, 163 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 160, 161 prior to engagingthe respective input clutches 162, 163. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms164, 165, 166, 167, 168, 169, 170, 171 and 172. The torque transmittingmechanisms 164 and 165 comprise braking synchronizers, and the torquetransmitting mechanisms 166, 167, 168, 169, 170, 171 and 172 compriserotating synchronizers.

[0079] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 160, 161 (i.e. through the clutch162 to the synchronizers 166, 167, 168 and through the clutch 163 to thering gear member 144). The ring gear member 124 is continuouslyconnected with the planet carrier assembly member 136 through theinterconnecting member 174. The planet carrier assembly member 126 iscontinuously connected with the sun gear member 132 through theinterconnecting member 176. The planet carrier assembly member 146 iscontinuously connected with the ring gear member 134 and the outputshaft 19 through the interconnecting member 178. The ring gear member154 is continuously connected with the transmission housing 180.

[0080] The planet carrier assembly member 126 is selectively connectablewith the transmission housing 180 through the braking synchronizer 164.The ring gear member 124 is selectively connectable with thetransmission housing 180 through the braking synchronizer 165. Theplanet carrier assembly member 126 is selectively connectable with theinput shaft 17 through the input clutch 162 and the rotatingsynchronizer 166. The sun gear member 122 is selectively connectablewith the input shaft 17 through the input clutch 162 and the rotatingsynchronizer 167. The planet carrier assembly member 136 is selectivelyconnectable with the input shaft 17 through the input clutch 162 and therotating synchronizer 168. The planet carrier assembly member 146 isselectively connectable with the planet carrier assembly member 156through the rotating synchronizer 169. The planet carrier assemblymember 146 is selectively connectable with the sun gear member 152through the rotating synchronizer 170. The sun gear member 142 isselectively connectable with the planet carrier assembly member 156through the rotating synchronizer 171. The sun gear member 142 isselectively connectable with the sun gear member 152 through therotating synchronizer 172.

[0081] As shown in FIG. 2b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

[0082] The reverse speed ratio is established with the engagement of theinput clutch 162, the braking synchronizer 165 and the rotatingsynchronizer 166. The input clutch 162 and the rotating synchronizer 166connect the planet carrier assembly member 126 to the input shaft 17.The braking synchronizer 165 connects the ring gear member 124 to thetransmission housing 180. The planet carrier assembly member 126 and thesun gear member 132 rotate at the same speed as the input shaft 17. Thering gear member 124 and the planet carrier assembly member 136 do notrotate. The ring gear member 134 and the planet carrier assembly member146 rotate at the same speed as the output shaft 19. The ring gearmember 134, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the sun gear member 132 and the ringgear/sun gear tooth ratio of the planetary gear set 130. The numericalvalue of the reverse speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 130.

[0083] The first forward speed ratio is established with the engagementof the input clutch 162, the braking synchronizer 165 and the rotatingsynchronizer 167. The input clutch 162 and the rotating synchronizer 167connect the sun gear member 122 to the input shaft 17. The brakingsynchronizer 165 connects the ring gear member 124 to the transmissionhousing 180. The sun gear member 122 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 126 rotates at thesame speed as the sun gear member 132. The ring gear member 124 and theplanet carrier assembly member 136 do not rotate. The planet carrierassembly member 126 rotates at a speed determined from the speed of thesun gear member 122 and the ring gear/sun gear tooth ratio of theplanetary gear set 120. The ring gear member 134 and the planet carrierassembly member 146 rotate at the same speed as the output shaft 19. Thering gear member 134, and therefore the output shaft 19, rotates at aspeed determined from the speed of the sun gear member 132 and the ringgear/sun gear tooth ratio of the planetary gear set 130. The numericalvalue of the first forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear set 120, 130.

[0084] The second forward speed ratio is established with the engagementof the input clutch 163 and the rotating synchronizer 169, 172. Theinput clutch 163 connects the ring gear member 144 to the input shaft17. The rotating synchronizer 169 connects the planet carrier assemblymember 146 to the planet carrier assembly member 156. The rotatingsynchronizer 172 connects the sun gear member 142 to the sun gear member152. The sun gear member 142 rotates at the same speed as the sun gearmember 152. The planet carrier assembly members 146, 156 rotate at thesame speed as the output shaft 19. The ring gear member 144 rotates atthe same speed as the input shaft 17. The planet carrier assembly member146, and therefore the output shaft 19, rotates at a speed determinedfrom the speed of the ring gear member 144, the speed of the sun gearmember 142 and the ring gear/sun gear tooth ratio of the planetary gearset 140. The ring gear member 154 does not rotate. The planet carrierassembly member 156 rotates at a speed determined from the speed of thesun gear member 152 and the ring gear/sun gear tooth ratio of theplanetary gear set 150. The numerical value of the second forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 140, 150.

[0085] The third forward speed ratio is established with the engagementof the input clutch 162, the braking synchronizer 164 and the rotatingsynchronizer 167. The input clutch 162 and the rotating synchronizer 167connect the sun gear member 122 to the input shaft 17. The brakingsynchronizer 164 connects the planet carrier assembly member 126 to thetransmission housing 180. The sun gear member 122 rotates at the samespeed as the input shaft 17. The planet carrier assembly member 126 andthe sun gear member 132 do not rotate. The ring gear member 124 rotatesat the same speed as the planet carrier assembly member 136. The ringgear member 124 rotates at a speed determined from the speed of the sungear member 122 and the ring gear/sun gear tooth ratio of the planetarygear set 120. The ring gear member 134 and the planet carrier assemblymember 146 rotate at the same speed as the output shaft 19. The ringgear member 134, and therefore the output shaft 19, rotates at a speeddetermined from the speed of the planet carrier assembly member 136 andthe ring gear/sun gear tooth ratio of the planetary gear set 130. Thenumerical value of the third forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 120, 130.

[0086] The fourth forward speed ratio is established with the engagementof the input clutch 163 and the rotating synchronizers 169, 171. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the fourth forward speed ratio is 1.

[0087] The fifth forward speed ratio is established with the engagementof the input clutch 162, the braking synchronizer 164 and the rotatingsynchronizer 168. The input clutch 162 and the rotating synchronizer 168connect the planet carrier assembly member 136 to the input shaft 17.The braking synchronizer 164 connects the planet carrier assembly member126 to the transmission housing 180. The planet carrier assembly member126 and the sun gear member 132 do not rotate. The ring gear member 124and the planet carrier assembly member 136 rotate at the same speed asthe input shaft 17. The ring gear member 134 and the planet carrierassembly member 146 rotate at the same speed as the output shaft 19. Thering gear member 134, and therefore the output shaft 19, rotates at aspeed determined from the speed of the planet carrier assembly member136 and the ring gear/sun gear tooth ratio of the planetary gear set130. The numerical value of the fifth forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set130.

[0088] The sixth forward speed ratio is established with the engagementof the input clutch 163 and the rotating synchronizers 170, 171. Theinput clutch 163 connects the ring gear member 144 to the input shaft17. The rotating synchronizer 170 connects the planet carrier assemblymember 146 to the sun gear member 152. The rotating synchronizer 171connects the sun gear member 142 to the planet carrier assembly member156. The sun gear member 142 rotates at the same speed as the planetcarrier assembly member 156. The planet carrier assembly member 146 andthe sun gear member 152 rotate at the same speed as the output shaft 19.The ring gear member 144 rotates at the same speed as the input shaft17. The planet carrier assembly member 146, and therefore the outputshaft 19, rotates at a speed determined from the speed of the ring gearmember 144, the speed of the sun gear member 142 and the ring gear/sungear tooth ratio of the planetary gear set 140. The ring gear member 154does not rotate. The planet carrier assembly member 156 rotates at aspeed determined from the speed of the sun gear member 152 and the ringgear/sun gear tooth ratio of the planetary gear set 150. The numericalvalue of the sixth forward speed ratio is determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 140, 150.

[0089] As set forth above, the truth table of FIG. 2b describes theengagement sequence of the torque transmitting mechanisms utilized toprovide a reverse drive ratio and six forward speed ratios. The truthtable also provides an example of the ratios that can be attained withthe family members shown in FIG. 2a utilizing the sample tooth ratiosgiven in FIG. 2b. The R1/S1 value is the tooth ratio of the planetarygear set 120; the R2/S2 value is the tooth ratio of the planetary gearset 130; the R3/S3 value is the tooth ratio of the planetary gear set140; and the R4/S4 value is the tooth ratio of the planetary gear set150. Also shown in FIG. 2b are the ratio steps between single stepratios in the forward direction as well as the reverse to first ratiostep. For example, the first to second step ratio is 1.50. Those skilledin the art will recognize that since torque transmitting mechanisms 166and 167 (168) are connected to a common member, input clutch 162, andthey are not engaged at the same time for any of the speed ratios, thepair can be executed as a double (triple) synchronizer to reduce contentand cost. Similarly, torque transmitting mechanisms pair 172 and 170 canbe implemented as a double synchronizer.

[0090] Turning the FIG. 3a, a powertrain 210 having a conventionalengine 12, a planetary transmission 214, and conventional final drivemechanism 16 is shown.

[0091] The planetary transmission 214 includes an input shaft 17continuously connected with the engine 12, a planetary gear arrangement218, and an output shaft 19 continuously connected with the final drivemechanism 16. The planetary gear arrangement 218 includes four planetarygear sets 220, 230, 240 and 250.

[0092] The planetary gear set 220 includes a sun gear member 222, a ringgear member 224, and a planet carrier assembly member 226. The planetcarrier assembly member 226 includes a plurality of pinion gears 227rotatably mounted on a carrier member 229 and disposed in meshingrelationship with both the sun gear member 222 and the ring gear member224.

[0093] The planetary gear set 230 includes a sun gear member 232, a ringgear member 234, and a planet carrier assembly member 236. The planetcarrier assembly member 236 includes a plurality of pinion gears 237rotatably mounted on a carrier member 239 and disposed in meshingrelationship with both the sun gear member 232 and the ring gear member234.

[0094] The planetary gear set 240 includes a sun gear member 242, a ringgear member 244, and a planet carrier assembly member 246. The planetcarrier assembly member 246 includes a plurality of intermeshing piniongears 247, 248 rotatably mounted on a carrier member 249 and disposed inmeshing relationship with the ring gear member 244 and the sun gearmember 242, respectively.

[0095] The planetary gear set 250 includes a sun gear member 252, a ringgear member 254, and a planet carrier assembly member 256. The planetcarrier assembly member 256 includes a plurality of intermeshing piniongears 257, 258 rotatably mounted on a carrier member 259 and disposed inmeshing relationship with the ring gear member 254 and the sun gearmember 252, respectively.

[0096] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 220, 230, 240 and 250 are divided into firstand second transmission subsets 260, 261 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 260 includes planetary gear sets 220 and 230, andtransmission subset 261 includes planetary gear sets 240 and 250. Theoutput shaft 19 is continuously connected with members of both subsets260 and 261.

[0097] As mentioned above, the first and second input clutches 262, 263are alternatively engaged for transmitting power from the input shaft 17to transmission subset 260 or transmission subset 261. The first andsecond input clutches 262, 263 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 260, 261 prior to engagingthe respective input clutches 262, 263. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms264, 265, 266, 267, 268, 269, 270, 271 and 272. The torque transmittingmechanisms 264 and 265 comprise braking synchronizers, and the torquetransmitting mechanisms 266, 267, 268, 269, 270, 271 and 272 compriserotating synchronizers.

[0098] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 260, 261 (i.e. through the clutch262 to the synchronizers 266, 267, 268 and through the clutch 263 to thering gear member 244). The ring gear member 224 is continuouslyconnected with the sun gear member 232 through the interconnectingmember 274. The planet carrier assembly member 226 is continuouslyconnected with the planet carrier assembly member 236 through theinterconnecting member 276. The planet carrier assembly member 246 iscontinuously connected with the ring gear member 234 and the outputshaft 19 through the interconnecting member 278. The sun gear member 252is continuously connected with the transmission housing 280.

[0099] The ring gear member 224 is selectively connectable with thetransmission housing 280 through the braking synchronizer 264. Theplanet carrier assembly member 236 is selectively connectable with thetransmission housing 280 through the braking synchronizer 265. The ringgear member 224 is selectively connectable with the input shaft 17through the input clutch 262 and the rotating synchronizer 266. The sungear member 222 is selectively connectable with the input shaft 17through the input clutch 262 and the rotating synchronizer 267. Theplanet carrier assembly member 236 is selectively connectable with theinput shaft 17 through the input clutch 262 and the rotatingsynchronizer 268. The planet carrier assembly member 246 is selectivelyconnectable with the ring gear member 254 through the rotatingsynchronizer 269. The planet carrier assembly member 246 is selectivelyconnectable with the planet carrier assembly member 256 through therotating synchronizer 270. The sun gear member 242 is selectivelyconnectable with the ring gear member 254 through the rotatingsynchronizer 271. The sun gear member 242 is selectively connectablewith the planet carrier assembly member 256 through the rotatingsynchronizer 272.

[0100] As shown in FIG. 3b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

[0101] The reverse speed ratio is established with the engagement of theinput clutch 262, the braking synchronizer 265 and the rotatingsynchronizer 266. The input clutch 262 and the rotating synchronizer 266connect the ring gear member 224 to the input shaft 17. The brakingsynchronizer 265 connects the planet carrier assembly member 236 to thetransmission housing 280. The ring gear member 224 and the sun gearmember 232 rotate at the same speed as the input shaft 17. The planetcarrier assembly members 226, 236 do not rotate. The ring gear member234 and the planet carrier assembly member 246 rotate at the same speedas the output shaft 19. The ring gear member 234, and therefore theoutput shaft 19, rotates at a speed determined from the speed of the sungear member 232 and the ring gear/sun gear tooth ratio of the planetarygear set 230. The numerical value of the reverse speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 230.

[0102] The first forward speed ratio is established with the engagementof the input clutch 262, the braking synchronizer 265 and the rotatingsynchronizer 267. The input clutch 262 and the rotating synchronizer 267connect the sun gear member 222 to the input shaft 17. The brakingsynchronizer 265 connects the planet carrier assembly member 236 to thetransmission housing 280. The sun gear member 222 rotates at the samespeed as the input shaft 17. The planet carrier assembly members 226,236 do not rotate. The ring gear member 224 rotates at the same speed asthe sun gear member 232. The ring gear member 224 rotates at a speeddetermined from the speed of the sun gear member 222 and the ringgear/sun gear tooth ratio of the planetary gear set 220. The ring gearmember 234 and the planet carrier assembly member 246 rotate at the samespeed as the output shaft 19. The ring gear member 234, and thereforethe output shaft 19, rotates at a speed determined from the speed of thesun gear member 232 and the ring gear/sun gear tooth ratio of theplanetary gear set 230. The numerical value of the first forward speedratio is determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear set 220, 230.

[0103] The second forward speed ratio is established with the engagementof the input clutch 263 and the rotating synchronizer 269, 272. Theinput clutch 263 connects the ring gear member 244 to the input shaft17. The rotating synchronizer 269 connects the planet carrier assemblymember 246 to the ring gear member 254. The rotating synchronizer 272connects the sun gear member 242 to the planet carrier assembly member256. The sun gear member 242 rotates at the same speed as the planetcarrier assembly member 256. The planet carrier assembly member 246 andthe ring gear member 254 rotate at the same speed as the output shaft19. The ring gear member 244 rotates at the same speed as the inputshaft 17. The planet carrier assembly member 246, and therefore theoutput shaft 19, rotates at a speed determined from the speed of thering gear member 244, the speed of the sun gear member 242 and the ringgear/sun gear tooth ratio of the planetary gear set 240. The sun gearmember 252 does not rotate. The planet carrier assembly member 256rotates at a speed determined from the speed of the ring gear member 254and the ring gear/sun gear tooth ratio of the planetary gear set 250.The numerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets240, 250.

[0104] The third forward speed ratio is established with the engagementof the input clutch 262 and the rotating synchronizers 266, 268. In thisconfiguration, the input shaft 17 is directly connected to the outputshaft 19. The numerical value of the third forward speed ratio is 1.

[0105] The fourth forward speed ratio is established with the engagementof the input clutch 263 and the rotating synchronizers 270, 271. Theinput clutch 263 connects the ring gear member 244 to the input shaft17. The rotating synchronizer 270 connects the planet carrier assemblymember 246 to the planet carrier assembly member 256. The rotatingsynchronizer 271 connects the sun gear member 242 to the ring gearmember 254. The sun gear member 242 rotates at the same speed as thering gear member 254. The planet carrier assembly members 246, 256rotate at the same speed as the output shaft 19. The ring gear member244 rotates at the same speed as the input shaft 17. The planet carrierassembly member 246, and therefore the output shaft 19, rotates at aspeed determined from the speed of the ring gear member 244, the speedof the sun gear member 242 and the ring gear/sun gear tooth ratio of theplanetary gear set 240. The sun gear member 252 does not rotate. Theplanet carrier assembly member 256 rotates at a speed determined fromthe speed of the ring gear member 254 and the ring gear/sun gear toothratio of the planetary gear set 250. The numerical value of the fourthforward speed ratio is determined utilizing the ring gear/sun gear toothratios of the planetary gear sets 240, 250.

[0106] The fifth forward speed ratio is established with the engagementof the input clutch 262, the braking synchronizer 264 and the rotatingsynchronizer 268. The input clutch 262 and the rotating synchronizer 268connect the planet carrier assembly member 236 to the input shaft 17.The braking synchronizer 264 connects the ring gear member 224 to thetransmission housing 280. The ring gear member 224 and the sun gearmember 232 do not rotate. The planet carrier assembly members 226, 236rotate at the same speed as the input shaft 17. The ring gear member 234and the planet carrier assembly member 246 rotate at the same speed asthe output shaft 19. The ring gear member 234, and therefore the outputshaft 19, rotates at a speed determined from the speed of the planetcarrier assembly member 236 and the ring gear/sun gear tooth ratio ofthe planetary gear set 230. The numerical value of the fifth forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 230.

[0107] The sixth forward speed ratio is established with the engagementof the input clutch 263 and the rotating synchronizers 271, 272. Theinput clutch 263 connects the ring gear member 244 to the input shaft17. The rotating synchronizer 271 connects the sun gear member 242 tothe ring gear member 254. The rotating synchronizer 272 connects the sungear member 242 to the planet carrier assembly member 256. The sun gearmember 242 and the planetary gear set 250 do not rotate. The planetcarrier assembly member 246 rotates at the same speed as the outputshaft 19. The ring gear member 244 rotates at the same speed as theinput shaft 17. The planet carrier assembly member 246, and thereforethe output shaft 19, rotates at a speed determined from the speed of thering gear member 244 and the ring gear/sun gear tooth ratio of theplanetary gear set 240. The numerical value of the sixth forward speedratio is determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 240.

[0108] As previously set forth, the truth table of FIG. 3b describes thecombinations of engagements utilized for six forward speed ratios andone reverse speed ratio. The truth table also provides an example ofspeed ratios that are available with the family member described above.These examples of speed ratios are determined the tooth ratios given inFIG. 3b. The R1/S1 value is the tooth ratio of the planetary gear set220; the R2/S2 value is the tooth ratio of the planetary gear set 230;the R3/S3 value is the tooth ratio of the planetary gear set 240; andthe R4/S4 value is the tooth ratio of the planetary gear set 250. Alsodepicted in FIG. 3b is a chart representing the ratio steps betweenadjacent forward speed ratios and the reverse speed ratio. For example,the first to second ratio interchange has a step of 2.00.

[0109] A powertrain 310, shown in FIG. 4a, includes the engine 12, aplanetary transmission 314, and the final drive mechanism 16. Theplanetary transmission 314 includes an input shaft 17 continuouslyconnected with the engine 12, a planetary gear arrangement 318, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 318 includes four planetary gear sets320, 330, 340 and 350.

[0110] The planetary gear set 320 includes a sun gear member 322, a ringgear member 324, and a planet carrier assembly member 326. The planetcarrier assembly member 326 includes a plurality of pinion gears 327rotatably mounted on a carrier member 329 and disposed in meshingrelationship with both the sun gear member 322 and the ring gear member324.

[0111] The planetary gear set 330 includes a sun gear member 332, a ringgear member 334, and a planet carrier assembly member 336. The planetcarrier assembly member 336 includes a plurality of pinion gears 337rotatably mounted on a carrier member 339 and disposed in meshingrelationship with both the sun gear member 332 and the ring gear member334.

[0112] The planetary gear set 340 includes a sun gear member 342, a ringgear member 344, and a planet carrier assembly member 346. The planetcarrier assembly member 346 includes a plurality of intermeshing piniongears 347, 348 rotatably mounted on a carrier member 349 and disposed inmeshing relationship with the ring gear member 344 and the sun gearmember 342, respectively.

[0113] The planetary gear set 350 includes a sun gear member 352, a ringgear member 354, and a planet carrier assembly member 356. The planetcarrier assembly member 356 includes a plurality of intermeshing piniongears 357, 358 rotatably mounted on a carrier member 359 and disposed inmeshing relationship with the ring gear member 354 and the sun gearmember 352, respectively.

[0114] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 320, 330, 340 and 350 are divided into firstand second transmission subsets 360, 361 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 360 includes planetary gear sets 320 and 330, andtransmission subset 361 includes planetary gear sets 340 and 350. Theoutput shaft 19 is continuously connected with members of both subsets360 and 361.

[0115] As mentioned above, the first and second input clutches 362, 363are alternatively engaged for transmitting power from the input shaft 17to transmission subset 360 or transmission subset 361. The first andsecond input clutches 362, 363 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 360, 361 prior to engagingthe respective input clutches 362, 363. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms364, 365, 366, 367, 368, 369, 370, 371 and 372. The torque transmittingmechanisms 364 and 365 comprise braking synchronizers, and the torquetransmitting mechanisms 366, 367, 368, 369, 370, 371 and 372 compriserotating synchronizers.

[0116] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 360, 361 (i.e. through the clutch362 to the synchronizers 366, 367, 368 and through the clutch 363 to thering gear member 344). The ring gear member 324 is continuouslyconnected with the sun gear member 332 through the interconnectingmember 374. The planet carrier assembly member 326 is continuouslyconnected with the planet carrier assembly member 336 through theinterconnecting member 376. The planet carrier assembly member 346 iscontinuously connected with the ring gear member 334 and the outputshaft 19 through the interconnecting member 378. The planet carrierassembly member 356 is continuously connected with the transmissionhousing 380.

[0117] The ring gear member 324 is selectively connectable with thetransmission housing 380 through the braking synchronizer 364. Theplanet carrier assembly member 336 is selectively connectable with thetransmission housing 380 through the braking synchronizer 365. The ringgear member 324 is selectively connectable with the input shaft 17through the input clutch 362 and the rotating synchronizer 366. The sungear member 322 is selectively connectable with the input shaft 17through the input clutch 362 and the rotating synchronizer 367. Theplanet carrier assembly member 326 is selectively connectable with theinput shaft 17 through the input clutch 362 and the rotatingsynchronizer 368. The planet carrier assembly member 346 is selectivelyconnectable with the ring gear member 354 through the rotatingsynchronizer 369. The planet carrier assembly member 346 is selectivelyconnectable with the sun gear member 352 through the rotatingsynchronizer 370. The sun gear member 342 is selectively connectablewith the ring gear member 354 through the rotating synchronizer 371. Thesun gear member 342 is selectively connectable with the sun gear member352 through the rotating synchronizer 372.

[0118] The truth tables given in FIGS. 4b, 5 b, 6 b, 7 b, 8 b, 9 b, 10 band 11 b show the engagement sequences for the torque transmittingmechanisms to provide at least five forward speed ratios and one reversespeed ratio. As shown and described above for the configurations inFIGS. 1a, 2 a and 3 a, those skilled in the art will understand from therespective truth tables how the speed ratios are established through theplanetary gear sets identified in the written description.

[0119] The truth table shown in FIG. 4b describes the engagementcombination and engagement sequence necessary to provide the reversedrive ratio and six forward speed ratios. A sample of the numericalvalues for the ratios is also provided in the truth table of FIG. 4b.These values are determined utilizing the ring gear/sun gear toothratios also given in FIG. 4b. The R1/S1 value is the tooth ratio for theplanetary gear set 320; the R2/S2 value is the tooth ratio for theplanetary gear set 330; the R3/S3 value is the tooth ratio for theplanetary gear set 340; and the R4/S4 value is the tooth ratio for theplanetary gear set 350. Also given in FIG. 4b is a chart describing thestep ratios between the adjacent forward speed ratios and the reverse tofirst forward speed ratio. For example, the first to second forwardspeed ratio step is 2.07.

[0120] Those skilled in the art will recognize that the numerical valuesof the reverse and fifth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 330. Thenumerical value of the first forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 320, 330.The numerical values of the second and fourth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 340, 350. The numerical value of the third forwardspeed ratio is 1. The numerical value of the sixth forward speed ratiois determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 340.

[0121] A powertrain 410 shown in FIG. 5a includes a conventional engine12, a planetary transmission 414, and a conventional final drivemechanism 16. The planetary transmission 414 includes an input shaft 17connected with the engine 12, a planetary gear arrangement 418, and anoutput shaft 19 continuously connected with the final drive mechanism16. The planetary gear arrangement 418 includes four planetary gear sets420, 430, 440 and 450.

[0122] The planetary gear set 420 includes a sun gear member 422, a ringgear member 424, and a planet carrier assembly member 426. The planetcarrier assembly member 426 includes a plurality of intermeshing piniongears 427, 428 rotatably mounted on a carrier member 429 and disposed inmeshing relationship with the ring gear member 424 and the sun gearmember 422, respectively.

[0123] The planetary gear set 430 includes a sun gear member 432, a ringgear member 434, and a planet carrier assembly member 436. The planetcarrier assembly member 436 includes a plurality of pinion gears 437rotatably mounted on a carrier member 439 and disposed in meshingrelationship with both the sun gear member 432 and the ring gear member434.

[0124] The planetary gear set 440 includes a sun gear member 442, a ringgear member 444, and a planet carrier assembly member 446. The planetcarrier assembly member 446 includes a plurality of intermeshing piniongears 447, 448 rotatably mounted on a carrier member 449 and disposed inmeshing relationship with the ring gear member 444 and the sun gearmember 442, respectively.

[0125] The planetary gear set 450 includes a sun gear member 452, a ringgear member 454, and a planet carrier assembly member 456. The planetcarrier assembly member 456 includes a plurality of pinion gears 457rotatably mounted on a carrier member 459 and disposed in meshingrelationship with both the sun gear member 452 and the ring gear member454.

[0126] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 420, 430, 440 and 450 are divided into firstand second transmission subsets 460, 461 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 460 includes planetary gear sets 420 and 430, andtransmission subset 461 includes planetary gear sets 440 and 450. Theoutput shaft 19 is continuously connected with members of both subsets460 and 461.

[0127] As mentioned above, the first and second input clutches 462, 463are alternatively engaged for transmitting power from the input shaft 17to transmission subset 460 or transmission subset 461. The first andsecond input clutches 462, 463 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 460, 461 prior to engagingthe respective input clutches 462, 463. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms464, 465, 466, 467, 468, 469, 470, 471 and 472. The torque transmittingmechanisms 464, 465 and 466 comprise braking synchronizers, and thetorque transmitting mechanisms 467, 468, 469, 470, 471 and 472 compriserotating synchronizers.

[0128] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 460, 461 (i.e. through the clutch462 to the synchronizers 467, 468 and through the clutch 463 to the ringgear member 444). The sun gear member 422 is continuously connected withthe ring gear member 434 through the interconnecting member 474. Theplanet carrier assembly member 426 is continuously connected with thesun gear member 432 through the interconnecting member 476. The planetcarrier assembly member 446 is continuously connected with the planetcarrier assembly member 436 and the output shaft 19 through theinterconnecting member 478. The ring gear member 454 is continuouslyconnected with the transmission housing 480.

[0129] The ring gear member 424 is selectively connectable with thetransmission housing 480 through the braking synchronizer 464. The ringgear member 434 is selectively connectable with the transmission housing480 through the braking synchronizer 465. The planet carrier assemblymember 426 is selectively connectable with the transmission housing 480through the braking synchronizer 466. The ring gear member 424 isselectively connectable with the input shaft 17 through the input clutch462 and the rotating synchronizer 467. The sun gear member 432 isselectively connectable with the input shaft 17 through the input clutch462 and the rotating synchronizer 468. The planet carrier assemblymember 446 is selectively connectable with the planet carrier assemblymember 456 through the rotating synchronizer 469. The planet carrierassembly member 446 is selectively connectable with the sun gear member452 through the rotating synchronizer 470. The sun gear member 442 isselectively connectable with the planet carrier assembly member 456through the rotating synchronizer 471. The sun gear member 442 isselectively connectable with the sun gear member 452 through therotating synchronizer 472.

[0130] As shown in FIG. 5b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio.

[0131]FIG. 5b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first ratio. For example, theratio step between the first and second forward ratios is 1.58. Thoseskilled in the art will recognize that the numerical values of thereverse, third and fifth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 420, 430.The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set430. The numerical values of the second and sixth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 440, 450. The numerical value of the fourth forwardspeed ratio is 1.

[0132] A powertrain 510, shown in FIG. 6a, includes a conventionalengine 12, a powertrain 514, and a conventional final drive mechanism16. The powertrain 514 includes an input shaft 17 connected with theengine 12, a planetary gear arrangement 518, and an output shaft 19continuously connected with the final drive mechanism 16. The planetarygear arrangement 518 includes four planetary gear sets 520, 530, 540 and550.

[0133] The planetary gear set 520 includes a sun gear member 522, a ringgear member 524, and a planet carrier assembly member 526. The planetcarrier assembly member 526 includes a plurality of pinion gears 527rotatably mounted on a carrier member 529 and disposed in meshingrelationship with both the sun gear member 522 and the ring gear member524.

[0134] The planetary gear set 530 includes a sun gear member 532, a ringgear member 534, and a planet carrier assembly member 536. The planetcarrier assembly member 536 includes a plurality of pinion gears 537rotatably mounted on a carrier member 539 and disposed in meshingrelationship with both the sun gear member 532 and the ring gear member534.

[0135] The planetary gear set 540 includes a sun gear member 542, a ringgear member 544, and a planet carrier assembly member 546. The planetcarrier assembly member 546 includes a plurality of intermeshing piniongears 547, 548 rotatably mounted on a carrier member 549 and disposed inmeshing relationship with the ring gear member 544 and the sun gearmember 542, respectively.

[0136] The planetary gear set 550 includes a sun gear member 552, a ringgear member 554, and a planet carrier assembly member 556. The planetcarrier assembly member 556 includes a plurality of intermeshing piniongears 557, 558 rotatably mounted on a carrier member 559 and disposed inmeshing relationship with the ring gear member 554 and the sun gearmember 552, respectively.

[0137] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 520, 530, 540 and 550 are divided into firstand second transmission subsets 560, 561 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 560 includes planetary gear sets 520 and 530, andtransmission subset 561 includes planetary gear sets 540 and 550. Theoutput shaft 19 is continuously connected with members of both subsets560 and 561.

[0138] As mentioned above, the first and second input clutches 562, 563are alternatively engaged for transmitting power from the input shaft 17to transmission subset 560 or transmission subset 561. The first andsecond input clutches 562, 563 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 560, 561 prior to engagingthe respective input clutches 562, 563. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms564, 565, 566, 567, 568, 569, 570, 571 and 572. The torque transmittingmechanisms 564 and 565 comprise braking synchronizers, and the torquetransmitting mechanisms 566, 567, 568, 569, 570, 571 and 572 compriserotating synchronizers.

[0139] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 560, 561 (i.e. through the clutch562 to the synchronizers 566, 567, 568 and through the clutch 563 to thering gear member 544). The planet carrier assembly member 526 iscontinuously connected with the ring gear member 534 through theinterconnecting member 574. The ring gear member 524 is continuouslyconnected with the sun gear member 532 through the interconnectingmember 576. The planet carrier assembly member 546 is continuouslyconnected with the planet carrier assembly member 536 and the outputshaft 19 through the interconnecting member 578. The planet carrierassembly member 556 is continuously connected with the transmissionhousing 580.

[0140] The sun gear member 522 is selectively connectable with thetransmission housing 580 through the braking synchronizer 564. Theplanet carrier assembly member 526 is selectively connectable with thetransmission housing 580 through the braking synchronizer 565. The sungear member 522 is selectively connectable with the input shaft 17through the input clutch 562 and the rotating synchronizer 566. The sungear member 532 is selectively connectable with the input shaft 17through the input clutch 562 and the rotating synchronizer 567. Theplanet carrier assembly member 526 is selectively connectable with theinput shaft 17 through the input clutch 562 and the rotatingsynchronizer 568. The planet carrier assembly member 546 is selectivelyconnectable with the ring gear member 554 through the rotatingsynchronizer 569. The planet carrier assembly member 546 is selectivelyconnectable with the sun gear member 552 through the rotatingsynchronizer 570. The sun gear member 542 is selectively connectablewith the ring gear member 554 through the rotating synchronizer 571. Thesun gear member 542 is selectively connectable with the sun gear member552 through the rotating synchronizer 572.

[0141] As shown in FIG. 6b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The chart of FIG. 6b describesthe ratio steps between adjacent forward speed ratios and the ratio stepbetween the reverse and first forward speed ratio.

[0142] Those skilled in the art, upon reviewing the truth table and theschematic representation of FIG. 6a can determine that the numericalvalues of the reverse, third and fifth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 520, 530. The numerical value of the first forwardspeed ratio is determined utilizing the ring gear/sun gear tooth ratioof the planetary gear set 530. The numerical values of the second andsixth forward speed ratios are determined utilizing the ring gear/sungear tooth ratios of the planetary gear set 540, 550. The numericalvalue of the fourth forward speed ratio is 1.

[0143] The sample speed ratios given in the truth table are determinedutilizing the tooth ratio values also given in FIG. 6b. R1/S1 value isthe tooth ratio of the planetary gear set 520; the R2/S2 value is thetooth ratio of the planetary gear set 530; the R3/S3 value is the toothratio of the planetary gear set 540; and the R4/S4 value is the toothratio of the planetary gear set 550.

[0144]FIGS. 7a and 7 b illustrate a transmission wherein one of thetorque transmitting mechanisms from a previously described configurationis eliminated to realize five forward speed ratios and a reverse speedratio. Specifically, the powertrain 610, shown in FIG. 7a is identicalto that shown in FIG. 5a, except that the rotating synchronizer 470 ofFIG. 5a has been eliminated.

[0145] Referring to FIG. 7a, a powertrain 610 is shown having aconventional engine 12, a planetary transmission 614, and a conventionalfinal drive mechanism 16. The planetary transmission 614 includes aninput shaft 17 connected with the engine 12, a planetary geararrangement 618, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 618 includesfour planetary gear sets 620, 630, 640 and 650.

[0146] The planetary gear set 620 includes a sun gear member 622, a ringgear member 624, and a planet carrier assembly member 626. The planetcarrier assembly member 626 includes a plurality of intermeshing piniongears 627, 628 rotatably mounted on a carrier member 629 and disposed inmeshing relationship with the ring gear member 624 and the sun gearmember 622, respectively.

[0147] The planetary gear set 630 includes a sun gear member 632, a ringgear member 634, and a planet carrier assembly member 636. The planetcarrier assembly member 636 includes a plurality of pinion gears 637rotatably mounted on a carrier member 639 and disposed in meshingrelationship with both the sun gear member 632 and the ring gear member634.

[0148] The planetary gear set 640 includes a sun gear member 642, a ringgear member 644, and a planet carrier assembly member 646. The planetcarrier assembly member 646 includes a plurality of intermeshing piniongears 647, 648 rotatably mounted on a carrier member 649 and disposed inmeshing relationship with the ring gear member 644 and the sun gearmember 642, respectively.

[0149] The planetary gear set 650 includes a sun gear member 652, a ringgear member 654, and a planet carrier assembly member 656. The planetcarrier assembly member 656 includes a plurality of pinion gears 657rotatably mounted on a carrier member 659 and disposed in meshingrelationship with both the sun gear member 652 and the ring gear member654.

[0150] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 620, 630, 640 and 650 are divided into firstand second transmission subsets 660, 661 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 660 includes planetary gear sets 620 and 630, andtransmission subset 661 includes planetary gear sets 640 and 650. Theoutput shaft 19 is continuously connected with members of both subsets660 and 661.

[0151] As mentioned above, the first and second input clutches 662, 663are alternatively engaged for transmitting power from the input shaft 17to transmission subset 660 or transmission subset 661. The first andsecond input clutches 662, 663 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 660, 661 prior to engagingthe respective input clutches 662, 663. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes eight torque transmitting mechanisms664, 665, 666, 667, 668, 669, 671 and 672. The torque transmittingmechanisms 664, 665 and 666 comprise braking synchronizers, and thetorque transmitting mechanisms 667, 668, 669, 671 and 672 compriserotating synchronizers.

[0152] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 660, 661 (i.e. through the clutch662 to the synchronizers 667, 668 and through the clutch 663 to the ringgear member 644). The sun gear member 622 is continuously connected withthe ring gear member 634 through the interconnecting member 674. Theplanet carrier assembly member 626 is continuously connected with thesun gear member 632 through the interconnecting member 676. The planetcarrier assembly member 646 is continuously connected with the planetcarrier assembly member 636 and the output shaft 19 through theinterconnecting member 678. The ring gear member 654 is continuouslyconnected with the transmission housing 680.

[0153] The ring gear member 624 is selectively connectable with thetransmission housing 680 through the braking synchronizer 664. The ringgear member 634 is selectively connectable with the transmission housing680 through the braking synchronizer 665. The planet carrier assemblymember 626 is selectively connectable with the transmission housing 680through the braking synchronizer 666. The ring gear member 624 isselectively connectable with the input shaft 17 through the input clutch662 and the rotating synchronizer 667. The sun gear member 632 isselectively connectable with the input shaft 17 through the input clutch662 and the rotating synchronizer 668. The planet carrier assemblymember 646 is selectively connectable with the planet carrier assemblymember 656 through the rotating synchronizer 669. The sun gear member642 is selectively connectable with the planet carrier assembly member656 through the rotating synchronizer 671. The planet carrier assemblymember 642 is selectively connectable with the planet carrier assemblymember 652 through the rotating synchronizer 672.

[0154] As shown in FIG. 7b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide five forwardspeed ratios and a reverse speed ratio. The truth table also provides aset of examples for the numerical values for each of the reverse andforward speed ratios. These numerical values have been determinedutilizing the ring gear/sun gear tooth ratios given in FIG. 7b. TheR1/S1 value is the tooth ratio of the planetary gear set 620; the R2/S2value is the tooth ratio of the planetary gear set 630; the R3/S3 valueis the tooth ratio of the planetary gear set 640; and the R4/S4 value isthe tooth ratio of the planetary gear set 650.

[0155] Those skilled in the art, upon reviewing the engagementcombinations, will recognize that the numerical values of the reverse,third and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 620, 630. Thenumerical value of the first forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 630. Thenumerical value of the second forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets640, 650. The numerical value of the fourth forward speed ratio is 1.

[0156] A powertrain 710, shown in FIG. 8a, has the conventional engine12, a planetary transmission 714, and the conventional final drivemechanism 16. The engine 12 is continuously connected with the inputshaft 17. The planetary transmission 714 is drivingly connected with thefinal drive mechanism 16 through the output shaft 19. The planetarytransmission 714 includes a planetary gear arrangement 718 that has afirst planetary gear set 720, a second planetary gear set 730, a thirdplanetary gear set 740, and a fourth planetary gear set 750.

[0157] The planetary gear set 720 includes a sun gear member 722, a ringgear member 724, and a planet carrier assembly member 726. The planetcarrier assembly member 726 includes a plurality of pinion gears 727rotatably mounted on a carrier member 729 and disposed in meshingrelationship with both the sun gear member 722 and the ring gear member724.

[0158] The planetary gear set 730 includes a sun gear member 732, a ringgear member 734, and a planet carrier assembly member 736. The planetcarrier assembly member 736 includes a plurality of intermeshing piniongears 737, 738 rotatably mounted on a carrier member 739 and disposed inmeshing relationship with the ring gear member 734 and the sun gearmember 732, respectively.

[0159] The planetary gear set 740 includes a sun gear member 742, a ringgear member 744, and a planet carrier assembly member 746. The planetcarrier assembly member 746 includes a plurality of intermeshing piniongears 747, 748 rotatably mounted on a carrier member 749 and disposed inmeshing relationship with the ring gear member 744 and the sun gearmember 742, respectively.

[0160] The planetary gear set 750 includes a sun gear member 752, a ringgear member 754, and a planet carrier assembly member 756. The planetcarrier assembly member 756 includes a plurality of intermeshing piniongears 757, 758 rotatably mounted on a carrier member 759 and disposed inmeshing relationship with the ring gear member 754 and the sun gearmember 752, respectively.

[0161] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 720, 730, 740 and 750 are divided into firstand second transmission subsets 760, 761 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 760 includes planetary gear sets 720 and 730, andtransmission subset 761 includes planetary gear sets 740 and 750. Theoutput shaft 19 is continuously connected with members of both subsets760 and 761.

[0162] As mentioned above, the first and second input clutches 762, 763are alternatively engaged for transmitting power from the input shaft 17to transmission subset 760 or transmission subset 761. The first andsecond input clutches 762, 763 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 760, 761 prior to engagingthe respective input clutches 762, 763. The preselection is achieved bymeans of electronically controlled synchronizers. As shown, theplanetary gear arrangement includes nine torque transmitting mechanisms764, 765, 766, 767, 768, 769, 770, 771 and 772. The torque transmittingmechanisms 764, 765 and 766 comprise braking synchronizers, and thetorque transmitting mechanisms 767, 768, 769, 770, 771 and 772 compriserotating synchronizers.

[0163] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 760, 761 (i.e. through the clutch762 to the synchronizers 767, 768 and through the clutch 763 to the ringgear member 744). The sun gear member 722 is continuously connected withthe planet carrier assembly member 736 through the interconnectingmember 774. The ring gear member 724 is continuously connected with thesun gear member 732 through the interconnecting member 776. The planetcarrier assembly member 746 is continuously connected with the planetcarrier assembly member 726 and the output shaft 19 through theinterconnecting member 778. The sun gear member 752 is continuouslyconnected with the transmission housing 780.

[0164] The ring gear member 734 is selectively connectable with thetransmission housing 780 through the braking synchronizer 764. The sungear member 732 is selectively connectable with the transmission housing780 through the braking synchronizer 765. The planet carrier assemblymember 736 is selectively connectable with the transmission housing 780through the braking synchronizer 766. The ring gear member 734 isselectively connectable with the input shaft 17 through the input clutch762 and the rotating synchronizer 767. The sun gear member 722 isselectively connectable with the input shaft 17 through the input clutch762 and the rotating synchronizer 768. The planet carrier assemblymember 746 is selectively connectable with the ring gear member 754through the rotating synchronizer 769. The planet carrier assemblymember 746 is selectively connectable with the planet carrier assemblymember 756 through the rotating synchronizer 770. The sun gear member742 is selectively connectable with the ring gear member 754 through therotating synchronizer 771. The sun gear member 742 is selectivelyconnectable with the planet carrier assembly member 756 through therotating synchronizer 772.

[0165] As shown in FIG. 8b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. Also given in the truth table isa set of numerical values that are attainable with the present inventionutilizing the ring gear/sun gear tooth ratios given in FIG. 8b. TheR1/S1 value is the tooth ratio of the planetary gear set 720; the R2/S2value is the tooth ratio of the planetary gear set 730; the R3/S3 valueis the tooth ratio of the planetary gear set 740; and the R4/S4 value isthe tooth ratio of the planetary gear set 750.

[0166]FIG. 8b also provides a chart of the ratio steps between adjacentforward ratios and between the reverse and first forward ratio. Forexample, the ratio step between the first and second forward ratios is1.96.

[0167] Those skilled in the art will recognize that the numerical valuesof the reverse and fifth forward speed ratios are determined utilizingthe ring gear/sun gear tooth ratios of the planetary gear sets 720, 730.The numerical value of the first forward speed ratio is determinedutilizing the ring gear/sun gear tooth ratio of the planetary gear set730. The numerical values of the second and fourth forward speed ratiosare determined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 740, 750. The numerical value of the third forwardspeed ratio is 1. The numerical value of the sixth forward speed ratiois determined utilizing the ring gear/sun gear tooth ratio of theplanetary gear set 740.

[0168] A powertrain 810, shown in FIG. 9a, has the conventional engine12, a planetary transmission 814, and the final drive mechanism 16. Theengine 12 is continuously connected with the input shaft 17. Theplanetary transmission 814 is drivingly connected with final drivemechanism 16 through output shaft 19. The planetary transmission 814includes a planetary gear arrangement 818 that has a first planetarygear set 820, a second planetary gear set 830, a third planetary gearset 840, and fourth planetary gear set 850.

[0169] The planetary gear set 820 includes a sun gear member 822, a ringgear member 824, and a planet carrier assembly member 826. The planetcarrier assembly member 826 includes a plurality of intermeshing piniongears 827, 828 rotatably mounted on a carrier member 829 and disposed inmeshing relationship with the ring gear member 824 and the sun gearmember 822, respectively.

[0170] The planetary gear set 830 includes a sun gear member 832, a ringgear member 834, and a planet carrier assembly member 836. The planetcarrier assembly member 836 includes a plurality of pinion gears 837rotatably mounted on a carrier member 839 and disposed in meshingrelationship with both the sun gear member 832 and the ring gear member834.

[0171] The planetary gear set 840 includes a sun gear member 842, a ringgear member 844, and a planet carrier assembly member 846. The planetcarrier assembly member 846 includes a plurality of intermeshing piniongears 847, 848 rotatably mounted on a carrier member 849 and disposed inmeshing relationship with the ring gear member 844 and the sun gearmember 842, respectively.

[0172] The planetary gear set 850 includes a sun gear member 852, a ringgear member 854, and a planet carrier assembly member 856. The planetcarrier assembly member 856 includes a plurality of intermeshing piniongears 857, 858 rotatably mounted on a carrier member 859 and disposed inmeshing relationship with the ring gear member 854 and the sun gearmember 852, respectively.

[0173] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 820, 830, 840 and 850 are divided into firstand second transmission subsets 860, 861 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 860 includes planetary gear sets 820 and 830, andtransmission subset 861 includes planetary gear sets 840 and 850. Theoutput shaft 19 is continuously connected with members of both subsets860 and 861.

[0174] As mentioned above, the first and second input clutches 862, 863are alternatively engaged for transmitting power from the input shaft 17to transmission subset 860 or transmission subset 861. The first andsecond input clutches 862, 863 are controlled electronically, and thedisengaged input clutch is gradually engaged while the engaged inputclutch is gradually disengaged to facilitate transfer of power from onetransmission subset to another. In this manner, shift quality ismaintained, as in an automatic transmission, while providing better fueleconomy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratioselection is preselected within the transmission subsets 860, 861 priorto engaging the respective input clutches 862, 863. The preselection isachieved by means of electronically controlled synchronizers. As shown,the planetary gear arrangement includes nine torque transmittingmechanisms 864, 865, 866, 867, 868, 869, 870, 871 and 872. The torquetransmitting mechanisms 864, 865 and 866 comprise braking synchronizers,and the torque transmitting mechanisms 867, 868, 869, 870, 871 and 872comprise rotating synchronizers.

[0175] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 860, 861 (i.e. through the clutch862 to the synchronizers 867, 868 and through the clutch 863 to the ringgear member 844). The sun gear member 822 is continuously connected withthe ring gear member 834 through the interconnecting member 874. Theplanet carrier assembly member 826 is continuously connected with thesun gear member 832 through the interconnecting member 876. The planetcarrier assembly member 846 is continuously connected with the planetcarrier assembly member 836 and the output shaft 19 through theinterconnecting member 878. The planet carrier assembly member 856 iscontinuously connected with the transmission housing 880.

[0176] The ring gear member 824 is selectively connectable with thetransmission housing 880 through the braking synchronizer 864. The ringgear member 834 is selectively connectable with transmission housing 880through the braking synchronizer 865. The planet carrier assembly member826 is selectively connectable with the transmission housing 880 throughthe braking synchronizer 866. The ring gear member 824 is selectivelyconnectable with the input shaft 17 through the input clutch 862 and therotating synchronizer 867. The sun gear member 832 is selectivelyconnectable with the input shaft 17 through the input clutch 862 and therotating synchronizer 868. The planet carrier assembly member 846 isselectively connectable with the ring gear member 854 through therotating synchronizer 869. The planet carrier assembly member 846 isselectively connectable with the sun gear member 852 through therotating synchronizer 870. The sun gear member 842 is selectivelyconnectable with the ring gear member 854 through the rotatingsynchronizer 871. The sun gear member 842 is selectively connectablewith the sun gear member 852 through the rotating synchronizer 872.

[0177] As shown in FIG. 9b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. A sample of numerical values forthe individual ratios is also given in the truth table of FIG. 9b. Thesenumerical values have been calculated using the ring gear/sun gear toothratios also given by way of example in FIG. 9b. The R1/S1 value is thetooth ratio of the planetary gear set 820; the R2/S2 value is the toothratio of planetary gear set 830; the R3/S3 value is the tooth ratio ofthe planetary gear set 840; and the R4/S4 value is the tooth ratio ofthe planetary gear set 850. FIG. 9b also describes the ratio stepsbetween adjacent forward ratios and between the reverse and firstforward ratio. For example, the ratio step between the first and secondforward ratios is 1.59.

[0178] Those skilled in the art will recognize that the numerical valuesof the reverse, third and fifth forward speed ratios are determinedutilizing the ring gear/sun gear tooth ratios of the planetary gear sets820, 830. The numerical value of the first forward speed ratio isdetermined utilizing the ring gear/sun gear tooth ratio of the planetarygear set 830. The numerical values of the second and sixth forward speedratios are determined utilizing the ring gear/sun gear tooth ratios ofthe planetary gear sets 840, 850. The numerical value of the fourthforward speed ratio is 1.

[0179] Referring to FIG. 10a, a powertrain 910 is shown having aconventional engine 12, a planetary transmission 914, and a conventionalfinal drive mechanism 16. The planetary transmission 914 includes aninput shaft 17 connected with the engine 12, a planetary geararrangement 918, and an output shaft 19 continuously connected with thefinal drive mechanism 16. The planetary gear arrangement 918 includesfour planetary gear sets 920, 930, 940 and 950.

[0180] The planetary gear set 920 includes a sun gear member 922, a ringgear member 924, and a planet carrier assembly member 926. The planetcarrier assembly member 926 includes a plurality of pinion gears 927rotatably mounted on a carrier member 929 and disposed in meshingrelationship with both the sun gear member 922 and the ring gear member924.

[0181] The planetary gear set 930 includes a sun gear member 932, a ringgear member 934, and a planet carrier assembly member 936. The planetcarrier assembly member 936 includes a plurality of pinion gears 937rotatably mounted on a carrier member 939 and disposed in meshingrelationship with both the sun gear member 932 and the ring gear member934.

[0182] The planetary gear set 940 includes a sun gear member 942, a ringgear member 944, and a planet carrier assembly member 946. The planetcarrier assembly member 946 includes a plurality of intermeshing piniongears 947, 948 rotatably mounted on a carrier member 949 and disposed inmeshing relationship with the ring gear member 944 and the sun gearmember 942, respectively.

[0183] The planetary gear set 950 includes a sun gear member 952, a ringgear member 954, and a planet carrier assembly member 956. The planetcarrier assembly member 956 includes a plurality of intermeshing piniongears 957, 958 rotatably mounted on a carrier member 959 and disposed inmeshing relationship with the ring gear member 954 and the sun gearmember 952, respectively.

[0184] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 920, 930, 940 and 950 are divided into firstand second transmission subsets 960, 961 which are alternatively engagedto provide odd number and even number speed ranges, respectively.Transmission subset 960 includes planetary gear sets 920 and 930, andtransmission subset 961 includes planetary gear sets 940 and 950. Theoutput shaft 19 is continuously connected with members of both subsets960 and 961.

[0185] In this family member, rather than having two input clutchesalternatively engaged for transmitting power from the input shaft 17 totransmission subset 960 or transmission subset 961, the first inputclutch is operatively replaced by the synchronizers 964, 965 asdescribed below. The input clutch 963 and synchronizers 964, 965 arecontrolled electronically, and the disengaged input clutch orsynchronizer is gradually disengaged to facilitate transfer of powerfrom one transmission subset to another. In this manner, shift qualityis maintained, as in an automatic transmission, while providing betterfuel economy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 960, 961 prior to engagingthe respective input clutch 963 or synchronizers 964, 965. Thepreselection is achieved by means of electronically controlledsynchronizers. As shown, the planetary gear arrangement includes ninetorque transmitting mechanisms 964, 965, 966, 967, 968, 969, 970, 971and 972. The torque transmitting mechanisms 964 and 965 comprise brakingsynchronizers, and the torque transmitting mechanisms 966, 967, 968,969, 970, 971 and 972 comprise rotating synchronizers.

[0186] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 960, 961 (i.e. through the clutch962 to the synchronizers 966, 967, 968 and through the clutch 963 to thering gear member 944). The planet carrier assembly member 926 iscontinuously connected with the ring gear member 934 through theinterconnecting member 974. The ring gear member 924 is continuouslyconnected with the sun gear member 932 through the interconnectingmember 976. The planet carrier assembly member 946 is continuouslyconnected with the planet carrier assembly member 936 and the outputshaft 19 through the interconnecting member 978. The sun gear member 952is continuously connected with the transmission housing 980.

[0187] The sun gear member 922 is selectively connectable with thetransmission housing 980 through the braking synchronizer 964. Theplanet carrier assembly member 926 is selectively connectable with thetransmission housing 980 through the braking synchronizer 965. The sungear member 922 is selectively connectable with the input shaft 17through the input clutch 962 and the rotating synchronizer 966. The sungear member 932 is selectively connectable with the input shaft 17through the input clutch 962 and the rotating synchronizer 967. Theplanet carrier assembly member 926 is selectively connectable with theinput shaft 17 through the input clutch 962 and the rotatingsynchronizer 968. The planet carrier assembly member 946 is selectivelyconnectable with the ring gear member 954 through the rotatingsynchronizer 969. The planet carrier assembly member 946 is selectivelyconnectable with the planet carrier assembly member 956 through therotating synchronizer 970. The sun gear member 942 is selectivelyconnectable with the ring gear member 954 through the rotatingsynchronizer 971. The sun gear member 942 is selectively connectablewith the planet carrier assembly member 956 through the rotatingsynchronizer 972.

[0188] As shown in FIG. 10b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of three to provide six forwardspeed ratios and a reverse speed ratio. The truth table also provides aset of examples for the numerical values for each of the reverse andforward speed ratios. These numerical values have been determinedutilizing the ring gear/sun gear tooth ratios given in FIG. 10b. TheR1/S1 value is the tooth ratio of the planetary gear set 920; the R2/S2value is the tooth ratio of the planetary gear set 930; the R3/S3 valueis the tooth ratio of the planetary gear set 940; and the R4/S4 value isthe tooth ratio of the planetary gear set 950.

[0189] Those skilled in the art, upon reviewing the engagementcombinations, will recognize that the numerical values of the reverse,third and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 920, 930. Thenumerical value of the first forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 930. Thenumerical values of the second and sixth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 940, 950. The numerical value of the fourth forwardspeed ratio is 1.

[0190] Referring to FIG. 11a, a powertrain 1010 is shown having aconventional engine 12, a planetary transmission 1014, and aconventional final drive mechanism 16. The planetary transmission 1014includes an input shaft 17 connected with the engine 12, a planetarygear arrangement 1018, and an output shaft 19 continuously connectedwith the final drive mechanism 16. The planetary gear arrangement 1018includes four planetary gear sets 1020, 1030, 1040 and 1050.

[0191] The planetary gear set 1020 includes a sun gear member 1022, aring gear member 1024, and a planet carrier assembly member 1026. Theplanet carrier assembly member 1026 includes a plurality of pinion gears1027 rotatably mounted on a carrier member 1029 and disposed in meshingrelationship with both the sun gear member 1022 and the ring gear member1024.

[0192] The planetary gear set 1030 includes a sun gear member 1032, aring gear member 1034, and a planet carrier assembly member 1036. Theplanet carrier assembly member 1036 includes a plurality of pinion gears1037 rotatably mounted on a carrier member 1039 and disposed in meshingrelationship with both the sun gear member 1032 and the ring gear member1034.

[0193] The planetary gear set 1040 includes a sun gear member 1042, aring gear member 1044, and a planet carrier assembly member 1046. Theplanet carrier assembly member 1046 includes a plurality of intermeshingpinion gears 1047, 1048 rotatably mounted on a carrier member 1049 anddisposed in meshing relationship with the ring gear member 1044 and thesun gear member 1042, respectively.

[0194] The planetary gear set 1050 includes a sun gear member 1052, aring gear member 1054, and a planet carrier assembly member 1056. Theplanet carrier assembly member 1056 includes a plurality of intermeshingpinion gears 1057, 1058 rotatably mounted on a carrier member 1059 anddisposed in meshing relationship with the ring gear member 1054 and thesun gear member 1052, respectively.

[0195] As a result of the dual clutch arrangement of the invention, thefour planetary gear sets 1020, 1030, 1040 and 1050 are divided intofirst and second transmission subsets 1060, 1061 which are alternativelyengaged to provide odd number and even number speed ranges,respectively. Transmission subset 1060 includes planetary gear sets 1020and 1030, and transmission subset 1061 includes planetary gear sets 1040and 1050. The output shaft 19 is continuously connected with members ofboth subsets 1060 and 1061.

[0196] In this family member, which is a derivative of the family membershown in FIG. 10a, rather than having two input clutches and ninesynchronizers, four input clutches and six synchronizers are utilized toachieve reduced content. The first input clutch and first, second andthird synchronizers in FIG. 10a are here operatively replaced by afirst, second and third input clutch 1066, 1067 and 1068 and the secondinput clutch in FIG. 10a remains here as a fourth input clutch 1063. Theinput clutches 1063, 1066, 1067 and 1068 are controlled electronically,and the disengaged input clutch is gradually engaged while the engagedinput clutch is gradually disengaged to facilitate transfer of powerfrom one transmission subset to another. In this manner, shift qualityis maintained, as in an automatic transmission, while providing betterfuel economy because no torque converter is required, and hydraulicsassociated with “wet” clutching are eliminated. All speed ratios arepreselected within the transmission subsets 1060, 1061 prior to engagingthe respective input clutch 1063, 1066, 1067 or 1068. The preselectionis achieved by means of electronically controlled synchronizers. Asshown, the planetary gear arrangement includes six torque transmittingmechanisms 1064, 1065, 1066, 1069, 1070, 1071 and 1072. The torquetransmitting mechanisms 1064 and 1065 comprise braking synchronizers,and the torque transmitting mechanisms 1069, 1070, 1071 and 1072comprise rotating synchronizers.

[0197] Accordingly, the input shaft 17 is alternately connected with thefirst and second transmission subsets 1060, 1061 (i.e. through theclutch 1066 to the sun gear member 1022, through the clutch 1067 to thesun gear member 1032, through the clutch 1068 to the planet carrierassembly member 1026 and through the clutch 1063 to the ring gear member1044). The planet carrier assembly member 1026 is continuously connectedwith the ring gear member 1034 through the interconnecting member 1074.The ring gear member 1024 is continuously connected with the sun gearmember 1032 through the interconnecting member 1076. The planet carrierassembly member 1046 is continuously connected with the planet carrierassembly member 1036 and the output shaft 19 through the interconnectingmember 1078. The sun gear member 1052 is continuously connected with thetransmission housing 1080.

[0198] The sun gear member 1022 is selectively connectable with thetransmission housing 1080 through the braking synchronizer 1064. Theplanet carrier assembly member 1026 is selectively connectable with thetransmission housing 1080 through the braking synchronizer 1065. The sungear member 1022 is selectively connectable with the input shaft 17through the rotating synchronizer 1066. The sun gear member 1032 isselectively connectable with the input shaft 17 through the rotatingsynchronizer 1067. The planet carrier assembly member 1026 isselectively connectable with the input shaft 17 through the rotatingsynchronizer 1068. The planet carrier assembly member 1046 isselectively connectable with the ring gear member 1054 through therotating synchronizer 1069. The planet carrier assembly member 1046 isselectively connectable with the planet carrier assembly member 1056through the rotating synchronizer 1070. The sun gear member 1042 isselectively connectable with the ring gear member 1054 through therotating synchronizer 1071. The sun gear member 1042 is selectivelyconnectable with the planet carrier assembly member 1056 through therotating synchronizer 1072.

[0199] As shown in FIG. 11b, and in particular the truth table disclosedtherein, the input clutches and torque transmitting mechanisms areselectively engaged in combinations of at least two to provide sixforward speed ratios and a reverse speed ratio. The truth table alsoprovides a set of examples for the numerical values for each of thereverse and forward speed ratios. These numerical values have beendetermined utilizing the ring gear/sun gear tooth ratios given in FIG.11b. The R1/S1 value is the tooth ratio of the planetary gear set 1020;the R2/S2 value is the tooth ratio of the planetary gear set 1030; theR3/S3 value is the tooth ratio of the planetary gear set 1040; and theR4/S4 value is the tooth ratio of the planetary gear set 1050.

[0200] Those skilled in the art, upon reviewing the engagementcombinations, will recognize that the numerical values of the reverse,third and fifth forward speed ratios are determined utilizing the ringgear/sun gear tooth ratios of the planetary gear sets 1020, 1030. Thenumerical value of the first forward speed ratio is determined utilizingthe ring gear/sun gear tooth ratio of the planetary gear set 1030. Thenumerical values of the second and sixth forward speed ratios aredetermined utilizing the ring gear/sun gear tooth ratios of theplanetary gear sets 1040, 1050. The numerical value of the fourthforward speed ratio is 1.

[0201] While the best modes for carrying out the invention have beendescribed in detail, those familiar with the art to which this inventionrelates will recognize various alternative designs and embodiments forpracticing the invention within the scope of the appended claims.

1. A multi-speed transmission comprising: an input shaft; an outputshaft; first, second, third and fourth planetary gear sets each havingfirst, second and third members; a first interconnecting membercontinuously interconnecting said first member of said first planetarygear set with said first member of said second planetary gear set; asecond interconnecting member continuously interconnecting said secondmember of said first planetary gear set with said second member of saidsecond planetary gear set; a third interconnecting member continuouslyinterconnecting a member of said first or second planetary gear set withsaid first member of said third planetary gear set and said outputshaft; said first member of said fourth planetary gear set beingcontinuously connected with a stationary member; a first input clutchconnected with said input shaft; a second input clutch selectivelyinterconnecting said input shaft with said second member of said thirdplanetary gear set; first and second torque-transmitting mechanismsselectively interconnecting members of said first and second planetarygear sets with said first input clutch; third, fourth, fifth and sixthtorque-transmitting mechanisms selectively interconnecting members ofsaid third planetary gear set with said second and third members of saidfourth planetary gear set; and seventh and eighth torque-transmittingmechanisms selectively interconnecting members of said first or secondplanetary gear set with said stationary member; a ninthtorque-transmitting mechanism selectively interconnecting a member ofsaid first or second planetary gear set with said first input clutch orwith said stationary member, said input clutches and torque-transmittingmechanisms being engaged in combinations of at least three to provide atleast six forward speed ratios and a reverse speed ratio.
 2. Thetransmission defined in claim 1, wherein said nine torque-transmittingmechanisms comprise synchronizers.
 3. The transmission defined in claim1, wherein said first, second, third, fourth, fifth, sixth and ninthtorque-transmitting mechanisms comprise rotating synchronizers, and saidseventh and eighth torque-transmitting mechanisms comprise brakingsynchronizers.
 4. The transmission defined in claim 1, wherein saidfirst, second, third, fourth, fifth and sixth torque transmittingmechanisms comprise rotating synchronizers, and said seventh, eighth andninth torque transmitting mechanisms comprise brakes.
 5. Thetransmission defined in claim 1, wherein said first input clutch isapplied for odd number speed ranges and said second input clutch isapplied for even number speed ranges.
 6. The transmission defined inclaim 1, wherein said first input clutch is applied for even numberspeed ranges and said second input clutch is applied for odd numberspeed ranges.
 7. The transmission defined in claim 1, wherein said firstinput clutch and said second input clutch are interchangeable to shiftfrom odd number speed ranges to even number speed ranges, and viceversa.
 8. The transmission defined in claim 1, wherein selected ones ofsaid nine torque-transmitting mechanisms are engaged prior to gearshifting to achieve shifting without torque interruptions.
 9. Thetransmission defined in claim 1, wherein at least two of saidsynchronizers comprise a double synchronizer to reduce cost and packagesize.
 10. A multi-speed transmission comprising: an input shaft; anoutput shaft; first, second, third and fourth planetary gear sets eachhaving first, second and third members; a first interconnecting membercontinuously interconnecting said first member of said first planetarygear set with said first member of said second planetary gear set; asecond interconnecting member continuously interconnecting said secondmember of said first planetary gear set with said second member of saidsecond planetary gear set; a third interconnecting member continuouslyinterconnecting a member of said first or second planetary gear set withsaid first member of said third planetary gear set and said outputshaft; said first member of said fourth planetary gear set beingcontinuously connected with a stationary member; a first input clutchcontinuously connected with said input shaft; a second input clutchselectively interconnecting said input shaft with said second member ofsaid third planetary gear set; and nine torque-transmitting mechanismsfor selectively interconnecting said members of said first, second,third or fourth planetary gear sets with said first or second inputclutch, said output shaft, said first, second or third interconnectingmember, said stationary member or with other members of said planetarygear sets, said input clutches and nine torque-transmitting mechanismsbeing engaged in combinations of at least three to establish at leastsix forward speed ratios and a reverse speed ratio between said inputshaft and said output shaft.
 11. The transmission defined in claim 10,wherein first and second of said nine torque-transmitting mechanisms areselectively operable for interconnecting members of said first andsecond planetary gear sets with said first input clutch.
 12. Thetransmission defined in claim 10, wherein a third, fourth, fifth andsixth of said nine torque-transmitting mechanisms are selectivelyoperable for interconnecting members of said third planetary gear setwith said second and third members of said fourth planetary gear set.13. The transmission defined in claim 10, wherein a seventh and eighthof said nine torque-transmitting mechanisms are operable for selectivelyinterconnecting members of said first or second planetary gear set withsaid stationary member.
 14. The transmission defined in claim 10,wherein a ninth of said nine torque-transmitting mechanisms isselectively operable for interconnecting a member of said first orsecond planetary gear set with said first input clutch or with saidstationary member.
 15. The transmission defined in claim 10, whereinplanet carrier assembly members of a plurality of said planetary gearsets are of the single pinion type.
 16. The transmission defined inclaim 10, wherein planet carrier assembly members of a plurality of saidplanetary gear sets are of the double pinion type.
 17. The transmissiondefined in claim 10, wherein each of said nine torque-transmittingmechanisms comprises a synchronizer.
 18. The transmission defined inclaim 10, wherein said first input clutch is applied for odd numberspeed ranges and said second input clutch is applied for even numberspeed ranges.
 19. The transmission defined in claim 10, wherein saidfirst input clutch is applied for even number speed ranges and saidsecond input clutch is applied for odd number speed ranges.
 20. Thetransmission defined in claim 10, wherein selected ones of said ninetorque-transmitting mechanisms are engaged prior to gear shifting toachieve shifting without torque interruptions.
 21. A multi-speedtransmission comprising: an input shaft; an output shaft; first, second,third and fourth planetary gear sets each having first, second and thirdmembers; a first interconnecting member continuously interconnectingsaid first member of said first planetary gear set with said firstmember of said second planetary gear set; a second interconnectingmember continuously interconnecting said second member of said firstplanetary gear set with said second member of said second planetary gearset; a third interconnecting member continuously interconnecting amember of said first or second planetary gear set with said first memberof said third planetary gear set and said output shaft; said firstmember of said fourth planetary gear set being continuously connectedwith a stationary member; first and second torque-transmittingmechanisms selectively interconnecting members of said first and secondplanetary gear set with said input shaft and, therefore, functioning asa first input clutch; a second input clutch selectively interconnectingsaid input shaft with said second member of said third planetary gearset; third, fourth, fifth and sixth torque-transmitting mechanismsselectively interconnecting members of said third planetary gear setwith said second and third members of said fourth planetary gear set;seventh and eighth torque-transmitting mechanisms selectivelyinterconnecting members of said first or second planetary gear sets withsaid stationary member; and a ninth torque-transmitting mechanismselectively interconnecting a member of said first or second planetarygear set with said input shaft; said input clutches andtorque-transmitting mechanisms being engaged in combinations of at leastthree to provide at least six forward speed ratios and a reverse speedratio.
 22. The transmission defined in claim 21, wherein said first andsecond torque transmitting mechanisms comprise clutches and said thirdthrough ninth of said nine torque-transmitting mechanisms comprisesynchronizers.
 23. The transmission defined in claim 21, wherein saidfirst input clutch is applied for odd number speed ranges and saidsecond input clutch is applied for even number speed ranges.
 24. Thetransmission defined in claim 21, wherein said first input clutch isapplied for even number speed ranges and said second input clutch isapplied for odd number speed ranges.
 25. The transmission defined inclaim 21, wherein said first input clutch and said second input clutchare interchangeable to shift from odd number speed ranges to even numberspeed ranges, and vice versa.
 26. The transmission defined in claim 21,wherein selected ones of said torque-transmitting mechanisms are engagedprior to gear shifting to achieve shifting without torque interruptions.27. The transmission defined in claim 21, wherein at least two of saidsynchronizers comprise a double synchronizer to reduce cost and packagesize.
 28. A multi-speed transmission comprising: an input shaft; anoutput shaft; first, second, third and fourth planetary gear sets eachhaving first, second and third members; a first interconnecting membercontinuously interconnecting said first member of said first planetarygear set with said first member of said second planetary gear set; asecond interconnecting member continuously interconnecting said secondmember of said first planetary gear set with said second member of saidsecond planetary gear set; a third interconnecting member continuouslyinterconnecting a member of said first or second planetary gear set withsaid first member of said third planetary gear set and said outputshaft; said first member of said fourth planetary gear set beingcontinuously connected with a stationary member; a first input clutchcontinuously connected with said input shaft; a second input clutchselectively interconnecting said input shaft with said second member ofsaid third planetary gear set; and eight torque-transmitting mechanismsfor selectively interconnecting said members of said first, second,third or fourth planetary gear sets with said first or second inputclutch, said output shaft, said first, second or third interconnectingmember, said stationary member or with other members of said planetarygear sets, said input clutches and eight torque-transmitting mechanismsbeing engaged in combinations of at least three to establish at leastfive forward speed ratios and a reverse speed ratio between said inputshaft and said output shaft.
 29. The transmission defined in claim 28,wherein first and second of said eight torque-transmitting mechanismsare selectively operable for interconnecting members of said first andsecond planetary gear sets with said first input clutch.
 30. Thetransmission defined in claim 28, wherein third, fourth and fifth ofsaid eight torque-transmitting mechanisms are selectively operable forinterconnecting members of said third planetary gear set with saidsecond and third members of said fourth planetary gear set.
 31. Thetransmission defined in claim 28, wherein sixth, seventh and eighth ofsaid eight torque-transmitting mechanisms are operable for selectivelyinterconnecting members of said first or second planetary gear set withsaid stationary member.
 32. The transmission defined in claim 28,wherein planet carrier assembly members of a plurality of said planetarygear sets are of the single pinion type.
 33. The transmission defined inclaim 28, wherein planet carrier assembly members of a plurality of saidplanetary gear sets are of the double pinion type.
 34. The transmissiondefined in claim 28, wherein each of said eight torque-transmittingmechanisms comprises a synchronizer.
 35. The transmission defined inclaim 28, wherein said first input clutch is applied for odd numberspeed ranges and said second input clutch is applied for even numberspeed ranges.
 36. The transmission defined in claim 28, wherein saidfirst input clutch is applied for even number speed ranges and saidsecond input clutch is applied for odd number speed ranges.
 37. Thetransmission defined in claim 28, wherein selected ones of said eighttorque-transmitting mechanisms are engaged prior to gear shifting toachieve shifting without torque interruptions.